The present invention relates generally to apparatus and methods for engaging tissue and/or closing openings through tissue, e.g., into body lumens, and more particularly to devices for closing a puncture in a blood vessel or other body lumen formed during a diagnostic or therapeutic procedure, and to methods for making and using such devices.
Catheterization and interventional procedures, such as angioplasty or stenting, generally are performed by inserting a hollow needle through a patient""s skin and intervening tissue into the vascular system. A guide wire may then be passed through the needle lumen into the patient""s blood vessel accessed by the needle. The needle may be removed, and an introducer sheath may be advanced over the guide wire into the vessel, e.g., in conjunction with or subsequent to a dilator. A catheter or other device may then be advanced through a lumen of the introducer sheath and over the guide wire into a position for performing a medical procedure. Thus, the introducer sheath may facilitate introduction of various devices into the vessel, while minimizing trauma to the vessel wall and/or minimizing blood loss during a procedure.
Upon completion of the procedure, the devices and introducer sheath may be removed, leaving a puncture site in the vessel wall. External pressure may be applied to the puncture site until clotting and wound sealing occur. This procedure, however, may be time consuming and expensive, requiring as much as an hour of a physician""s or nurse""s time. It is also uncomfortable for the patient, and requires that the patient remain immobilized in the operating room, catheter lab, or holding area. In addition, a risk of hematoma exists from bleeding before hemostasis occurs.
Various apparatus have been suggested for percutaneously sealing a vascular puncture by occluding the puncture site. For example, U.S. Pat. Nos. 5,192,302 and 5,222,974, issued to Kensey et al., describe the use of a biodegradable plug that may be delivered through an introducer sheath into a puncture site. When deployed, the plug may seal the vessel and provide hemostasis. Such devices, however, may be difficult to position properly with respect to the vessel, which may be particularly significant since it is generally undesirable to expose the plug material, e.g., collagen, within the bloodstream, where it may float downstream and risk causing an embolism.
Another technique has been suggested that involves percutaneously suturing the puncture site, such as that disclosed in U.S. Pat. No. 5,304,184, issued to Hathaway et al. Percutaneous suturing devices, however, may require significant skill by the user, and may be mechanically complex and expensive to manufacture.
U.S. Pat. No. 5,478,354, issued to Tovey et al., discloses a surgical fastener including an annular base having legs that, in a relaxed state, extend in a direction substantially perpendicular to a plane defined by the base and slightly inwards toward one another. During use, the fastener is fit around the outside of a cannula, thereby deflecting the legs outward. The cannula is placed in an incision, and the fastener is slid along the cannula until the legs pierce into skin tissue. When the cannula is withdrawn, the legs move towards one another back to the relaxed state to close the incision.
U.S. Pat. Nos. 5,007,921 and 5,026,390, issued to Brown, disclose staples that may be used to close a wound or incision. In one embodiment, an xe2x80x9cSxe2x80x9d shaped staple is disclosed that includes barbs that may be engaged into tissue on either side of the wound. In another embodiment, a ring-shaped staple is disclosed that includes barbs that project from the ring. Sides of the ring may be squeezed to separate the barbs further, and the barbs may be engaged into tissue on either side of a wound. The sides may then be released, causing the barbs to return closer together, and thereby pulling the tissue closed over the wound. These staples, however, have a large cross-sectional profile and therefore may not be easy to deliver through a percutaneous site to close an opening in a vessel wall.
Accordingly, devices for engaging tissue, e.g., to close a vascular puncture site, would be considered useful.
The present invention is directed to devices and methods for engaging tissue, e.g., to connect tissue segments together or to close and/or seal openings through tissue, such as in a wall of a body lumen. More particularly, the present invention is directed to vascular closure devices or clips for closing a puncture in a wall of a blood vessel formed during a diagnostic or therapeutic procedure, and to methods for making and using such devices.
In accordance with one aspect of the present invention, a device for closing an opening in a body lumen is provided that includes a generally annular-shaped body defining a plane, and a plurality of tissue engaging portions extending from the annular-shaped body substantially transversely with respect to the plane. In this embodiment, opposing tissue engaging portions, e.g., tines, are biased towards a substantially planar configuration lying in the plane. In one embodiment, the tissue engaging portions are biased towards one another, e.g., to close a puncture site or other opening through tissue. Alternatively, the tissue engaging portions may be biased away from one another.
In a preferred embodiment, the tissue engaging portions are integrally formed with the annular-shaped body, e.g., from a sheet of material, such as Nitinol or other superelastic alloy. The tissue engaging portions may be formed with the sheet of material in the substantially planar configuration. The tissue engaging portions may be deflected substantially transversely with respect to the plane to define a substantially transverse configuration. Alternatively, the device may be formed from an elongate wire or tube that may be wound to form an enclosed body.
In one embodiment, the tissue engaging portions, e.g., tines, optionally including barbs, for penetrating tissue, may be disposed substantially symmetrically about a central axis. Alternatively, the tissue engaging portions may be disposed in opposing sets along a linear axis.
In accordance with another aspect of the present invention, a device for engaging tissue, e.g., to close an opening in a body lumen, is provided that includes a generally annular-shaped body defining a plane. A plurality of tissue engaging portions extend from the annular-shaped body substantially transversely with respect to the plane. In a preferred embodiment, opposing tissue engaging portions of the device are biased towards a substantially planar configuration lying in the plane, as described above.
One or more expandable elements are disposed along a periphery of the annular-shaped body. The expandable elements are expandable between expanded and compressed states for increasing and reducing a peripheral dimension of the annular-shaped body, respectively. In one embodiment, the expandable elements may be an enclosed cell, e.g. a diamond-shaped cell, having a first width in the expanded state and a second width in the compressed state that is smaller than the first width. Alternatively, the expandable elements may be a zig-zag element or an arcuate element. Preferably, the expandable elements are biased to the expanded state, e.g., by appropriate heat treating of the expandable elements. Alternatively, the expandable elements may be biased to the compressed state.
In accordance with yet another aspect of the present invention, a clip, such as those described above, may be loaded on a delivery apparatus and used to close and/or seal an opening in a wall of a body lumen. The apparatus generally includes a sheath including proximal and distal ends defining a longitudinal axis therebetween. A housing is slidably disposed on the sheath, the housing including an annular cavity therein. A clip, such as those described above, is disposed within the cavity with the tissue engaging portions disposed substantially distally.
The housing is preferably actuable for advancing the clip distally towards the distal end of the sheath, e.g., to deploy the clip from the cavity. For example, the apparatus may include an actuator coupled to the housing, the actuator configured for advancing the housing distally to deploy the clip. Preferably, the actuator includes a spring mechanism for biasing the housing distally upon activation of the actuator. In addition, the apparatus may include a locator element for positioning the distal end of the sheath, such as a bleed back lumen or a mechanical locator.
During use, the distal end of the sheath, with the housing and clip near its proximal end, may be positioned through a patient""s skin along a passage and into a body lumen via an opening in the wall of the body lumen. One or more instruments may be introduced through the lumen of the sheath into the body lumen. A diagnostic or therapeutic procedure may be performed using the instruments at a location accessed via the body lumen. For example, in a preferred method, the body lumen is a peripheral blood vessel, such as a femoral artery, and the procedure may include angioplasty, atherectomy, stent delivery, delivery of a therapeutic agent, and/or tissue ablation.
The sheath may be manipulated, for example, with the aid of a locator element, to position the distal end with respect to the opening, e.g., to ensure that the clip engages a wall of the body lumen or other tissue proximal to the opening and is not advanced into the body lumen itself. The housing is advanced distally into the passage, e.g., until the tissue engaging portions of the clip substantially engage the wall of the body lumen or other tissue proximal to the opening in the wall of the body lumen. In addition, or alternatively, the clip may be deployed from the housing, for example, by an ejector within the housing. The sheath may then be withdrawn from the body lumen and passage, leaving the clip in the passage. As the distal end of the sheath is withdrawn through the clip, the tissue engaging portions automatically at least partially move towards the planar configuration to pull the engaged tissue together and substantially close the opening.
In one embodiment, the clip automatically expands to an enlarged cross-section when the clip is deployed from the housing. Thus, the clip may be compressed to facilitate loading into the housing, and thereby provide a reduced profile for the clip. This may be useful to allow the clip to be delivered through a smaller puncture.
A method according to the present invention may include causing a clip or other closure element to engage tissue, e.g., muscle, fat, fascia, and the like, that is proximal to the body lumen. Thus, unlike previously known methods, which are directed to closing the wall of a blood vessel using clips or sutures, the present invention may include deploying a closure element in the passage to cause it to engage intermediate tissue between the patient""s skin and the wall of the body lumen. When performed in this manner, the need to precisely position a closure element may be avoided as is required when engaging the wall of a vessel. Instead, the closure element may be located and delivered at a range of locations along the length of the passage yet still close and/or seal the passage. In effect, extra-vascular tissue is engaged to close the passage and thereby cause sealing of the wound. When the closure element is deployed, it is preferably planar, e.g., extending substantially parallel to the surface of the patient""s skin, although not necessarily so.
Other objects and features of the present invention will become apparent from consideration of the following description taken in conjunction with the accompanying drawings.